外面效率高，脚本里面效率低，很悲剧

脚本如下：
dbaccess -e old_migcardb@ids_car3g<
create temp table  tmp_pno(
        policyno char(22)
);

insert into tmp_pno
select a.policyno from picccardb:prpcmain a, new_midcardb@ids_car3g:migbypolicyno b where
a.proposalno = b.proposalno and b.flag = '0';

insert into  prpemain   select a.* from picccardb:prpcmain a
where  exists (select b.policyno from tmp_pno b where a.policyno=b.policyno);

update statistics;
!

主要慢在：
insert into  prpemain   select a.* from picccardb:prpcmain a
where  exists (select b.policyno from tmp_pno b where a.policyno=b.policyno);

请高手指点!! 收起